1. Field of the Invention
The invention relates to a gas sensor, particularly for exhaust gases of internal combustion engines, having a planar sensor element that is fixed in a longitudinal bore of a housing of a sealing arrangement that has two molded parts that can be pressed together by means of a spring element, and has a sealing material that is disposed between the molded parts and surrounds the sensor element.
2. Description of the Related Art
Gas sensors of the generic type are known. For example, DE 32 06 903 A1 discloses a gas sensor in which a planar sensor element is fixed in a longitudinal bore of a housing with two superposed, electrically-insulating molded parts. Between the molded parts, the sensor element is surrounded by an electrically-insulating powder that is compressed during assembly and is maintained in its compressed state by a spring element. Inside the housing, the powder forms a seal for the sensor element that separates a measured-gas chamber and a reference-gas chamber for the sensor element. It is known to use steatite as the sealing powder. A disadvantage of this is that, on the one hand, the steatite powder has a residual porosity that can cause leakages between the measured-gas chamber and the reference-gas chamber. Another disadvantage is that the steatite powder has a lower thermal expansion coefficient than the surrounding housing, so leakages can also occur due to heating of the gas sensor over the course of operation.